If you aren't sure whether your favorite Mac apps are compatible with OS X 10.6 Snow Leopard, SnowChecker can help. It scans your hard drive for apps, and then checks their compatibility against the info posted at snowleopard.wikidot.com. Not only does SnowChecker show you whether your apps are incompatible, it also gives you details notes about which features are broken.

To quickly see which apps are going to have issues under 10.6 and might need to be updated - either by you or by the app's developer - sort the list by status. Red Xs are apps whose functionality is completely borked in Snow Leopard, while yellow alerts represent apps where one or more inessential functions don't work. SnowChecker will sometimes even offer a workaround for these, like running the app in 32-bit mode or disabling Google Gears. Snow Leopard has been out for a while, but if you're just installing now, you should run SnowChecker first to figure out what your compatibility options are.